The Libertarian Party of New Hampshire is the New Hampshire affiliate of the Libertarian Party. The Libertarian Party of New Hampshire is the only state Libertarian Party in the country which currently has a house caucus, with three sitting state representatives.

On July 16, 1991, Calvin Warburton became the first sitting legislator to switch parties to the Libertarian Party, and the first Libertarian legislator in the contiguous 48 states. Warburton was serving his seventh term as a Republican state representative in New Hampshire when, at age 81, he switched to the Libertarian Party. In 1992, four Libertarians were elected to the New Hampshire House of Representatives. Warburton (who was re-elected to an eighth term), Andy Borsa, Don Gorman, and Finlay Rothhaus were all elected as state representatives. The four formed an officially recognized Libertarian Caucus with Gorman as the Libertarian Floor Leader.

Following the 2016 General Election, the Libertarian Party of New Hampshire gained ballot access back for the first time in 20 years as Max Abramson gained over 4% of the vote in the race for Governor.

On February 9, 2017, State Representative Caleb Q. Dyer changed his party affiliation from Republican to Libertarian. On May 10, 2017, State Representative Joseph Stallcop switched his party affiliation from Democratic to Libertarian. Following this announcement, the two formally requested a meeting space in the Legislative Office Building for caucusing prior to the session. The caucus held their first meeting on May 18, 2017. On June 27, Rep. Brandon Phinney became the third member of the House to announce he had changed his party registration to Libertarian.